Decidability

Question

Consider the following two decision problems
A. Whether a Turing machine takes more than 481 steps on input $\epsilon$ ?
B. Whether a Turing machine accepts the null string $\epsilon$?
Which of the following statements is true?

(A) Problem A is decidable but B is not

(B) Problem A is undecidable but B is decidable

(C) Both A and B are decidable

(D) Both A and B are undecidable

Comments

Where is this problem from?

---

@goxul Its a techtud question.

@srestha   can you please explain the 2nd part of the question

It says the string is empty, if we say that we don't give any string to turing machine and allow it run only on blanks then doesn't it mean that it is accepting empty string. Please tell me if am thinking in the right direction. Its creating confusion for me

---

2nd one is telling

Turing machine accepting NULL string, that means TM accepts nothing

Turing machine accepts nothing is always a undecidable problem

because, here TM cannot say 'yes' in any input. So, 'yes' answer of TM became invalid

So, it will be undecidable